<?php
 class test{
       private $a;
       private $b;
       static public $c;
       function set($insert){
             $this->a=$insert;
       }
       function get(){
           return $this->a;
       }
 }

 function amr($id){

       if($id >20){
           $b=new test();;
           return $b;
       }
 }

 $c=amr(30);
 $c->set('测试是否被改变');
 echo $c->get();

 $d=amr(40);
$d->set('改变成功');
 echo $d->get();

echo $c->get();
